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A chemical element, often simply called an element, is a type of atom which has a specific number of protons in its atomic nucleus (i.e., a specific atomic number, or Z). [ 1 ] The definitive visualisation of all 118 elements is the periodic table of the elements , whose history along the principles of the periodic law was one of the founding ...
Each distinct atomic number therefore corresponds to a class of atom: these classes are called the chemical elements. [5] The chemical elements are what the periodic table classifies and organizes. Hydrogen is the element with atomic number 1; helium, atomic number 2; lithium, atomic number 3; and so on.
This is a list of chemical elements and their atomic properties, ordered by Atomic number. ... Name Symbol Average atomic mass Electronegativity ... 1 20: Calcium: Ca ...
The following sortable table shows the 118 known elements. Atomic number, Element, and Symbol all serve independently as unique identifiers. Element names are those accepted by IUPAC. Block indicates the periodic table block for each element: red = s-block, yellow = p-block, blue = d-block, green = f-block.
People. Chemical elements are sometimes named after people, especially the synthetic elements discovered (created) after c. 1940. Very few are named after their discoverers, and only two have been named after living people: the element seaborgium was named after Glenn Seaborg, who was alive at the time of naming in 1997; [5] and in 2016 ...
Atomicity (chemistry) Atomicity is the total number of atoms present in a molecule of an element. For example, each molecule of oxygen (O 2) is composed of two oxygen atoms. Therefore, the atomicity of oxygen is 2. [1] In older contexts, atomicity is sometimes equivalent to valency. Some authors also use the term to refer to the maximum number ...
The atomic number or nuclear charge number (symbol Z) of a chemical element is the charge number of its atomic nucleus. For ordinary nuclei composed of protons and neutrons, this is equal to the proton number (np) or the number of protons found in the nucleus of every atom of that element. The atomic number can be used to uniquely identify ...
In the periodic table of the elements, each numbered row is a period. A period on the periodic table is a row of chemical elements. All elements in a row have the same number of electron shells. Each next element in a period has one more proton and is less metallic than its predecessor. Arranged this way, elements in the same group (column ...